母体肢体缺血预处理对宫内窘迫胎鼠复氧后海马神经元凋亡的影响

Effects of maternal limb ischemic preconditioning on fetal hippocampal neuron apoptosis induced by intrauterine distress-reoxygenation in rats

目的:观察母体的肢体缺血预处理(LIP)对宫内窘迫胎鼠复氧后海马神经元凋亡的影响。方法:采用微动脉夹阻断母鼠通向子宫和卵巢的动静脉15 min后开放以制备胎鼠宫内窘迫模型。孕19 d SD大鼠12只,随机分为4组:空白对照(S)组、LIP组、胎儿窘迫(FD)组和LIP+FD组。各组母鼠再灌注2 d时剖宫取活胎鼠12只断头取脑。TUNEL法测定胎鼠海马CA1区神经元凋亡情况,计算细胞凋亡指数;免疫组化法和Western blotting法测定Bcl-2和Bax蛋白的表达。结果:与S组比较,FD组和LIP+FD组胎鼠海马CA1区神经元凋亡指数增加(P<0.05),Bcl-2蛋白表达增加,Bax蛋白表达增加,Bcl-2/Bax比值降低;与S组比较,LIP组胎鼠海马CA1的Bcl-2、Bax蛋白表达及Bcl-2/Bax蛋白表达的比值无明显改变(P>0.05);与FD组比较,LIP+FD组细胞凋亡指数降低(P<0.05),Bcl-2/Bax比值增加。结论:母体肢体缺血预处理减轻了宫内窘迫胎鼠复氧后海马神经元的凋亡,其机制可能与Bcl-2蛋白表达的上调相关。

AIM： To evaluate the influence of maternal limb ischemic preconditioning （LIP） on the apoptosis of fetal hippocampal neurons induced by intrauterine distress-reoxygenation in rats. METHODS ： Intrauterine ischemia was induced by clamping the uterine and uterine branch of the ovarian blood vessels with aneurysm clamps for a period of 15 rain followed by removal of the clamps to permit reperfusion. Sprague-Dawley （SD） rats （n = 12） were randomly divided into 4 groups on the 19th pregnant day ： sham （S） group, LIP group, fetal distress （FD） group and LIP ＋ FD group. The cesarean birth occurred on embryonic day 21 to obtain 12 fetal rats alive in each group. The fetal rats were decapitated and the pyramidal cells in CA1 hippocampus were observed under light microscope. The neuronal apoptosis was detected by ter- minal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling （TUNEL） staining and the apoptotic rate was calculated. The expression of Bel-2 and Bax were detected by immunohistochemieal method and Western blotting. RE- SULTS： The rates of neuronal apoptosis in FD group and LIP ＋ FD group were significantly higher than that in S group （ P 〈 0.05 ）, while no significant difference was observed between S group and LIP group （ P 〉 0.05 ）. The expression of Bcl-2 and Bax in FD group and LIP ＋ FD group was significantly higher than that in S group （ P 〈 0.05 ）, while no signifi- cant difference was observed between S group and LIP group （P 〉0.05）. The ratio of Bcl-2/Bax was lower in FD group than that in S group. Compared with FD group, the rate of neuronal apoptosis was significantly lower （ P 〈 0.05 ）, while the ratio of Bcl-2/Bax was significantly higher （P 〈 0.05 ） in LIP ＋ FD group. CONCLUSION ： Maternal limb ischemiepreconditioning attenuates the apoptosis of fetal hippocampal neurons induced by intrauterine distress-reoxygenation,in rats, which may be associated with the up-regulation of Bcl-2 expression.